This protocol is used to obtain plasma lipoproteins and apolipoproteins to support a number of research projects in the Gladstone Institute of Cardiovascular Disease. The projects include investigations related to plasma lipoprotein metabolism, atherosclerosis, and neural cell function. The current project is designed to test the hypothesis that primary structure differences (amino acid sequence differences) between the three major isoforms of apolipoprotein-E account for different tertiary structures that affect isoform function in lipoprotein metabolism.